[PATCH v3 4/4] um: Prohibit the VM_CLONE flag in run_helper_thread()

[Tiwei Bie]

On 2025/3/20 16:32, Johannes Berg wrote:
> On Wed, 2025-03-19 at 21:55 +0800, Tiwei Bie wrote:
>> Directly creating helper threads with VM_CLONE using clone can
>> compromise the thread safety of errno. Since all these helper
>> threads have been converted to use os_run_helper_thread(), let's
>> prevent using this flag in run_helper_thread().
>>
> 
> I notice that now there's only one user left, the SIGWINCH handler,
> maybe we could change that too? Anyway not related to this patch, of
> course.

After taking a closer look, changing the SIGWINCH handler seems to
be tricky. It requires setting itself up as a session leader and
configuring the controlling terminal. So it seems that it can't be
turned into a real thread..

Regards,
Tiwei